Airman 1st Class Anthony Russell, 28th Civil Engineer Squadron water and fuels maintenance technician, tests pH levels of the base pool with a chlorometer during routine maintenance at the Bellamy Fitness Center on Ellsworth Air Force Base, S.D., Feb. 3, 2012. If the pH balance becomes too high, it can cause physical irritation such as burning of eyes and nose, if too low, it reduces the disinfectant potential of chlorine, resulting in unwanted algae growth. (U.S. Air Force photo by Airman 1st Class Zachary Hada/Released)